Fuzzy logic control of five-DOF active magnetic bearing system based on sliding mode concept

Abstract

In rotor dynamics, the deviation of the shaft is a common phenomenon. The main reasons for the deviation are non-linear attractive forces, harmonic disturbances, system parameter variations, etc. Active magnetic bearings (AMBs) are used to support the rotor inside the air gap in rotating machines, thus avoiding wear and tear and possible breakdowns. This paper proposes a fuzzy sliding mode-inspired control (FSMIC) technique for the five-degrees-of-freedom (DOF) AMB system in the presence of system uncertainties and measurement noises. The fuzzy logic is used to estimate the auxiliary control input of the sliding mode control (SMC) to attenuate the chattering. The variable gains are designed with the help of superintended fuzzy logic to bring more flexibility to the controller performance. The stability analysis is presented with the help of the Lyapunov function candidate. The simulation studies for the AMB system under distinct types of control techniques, i.e., PID, SMC, and FSMIC, illustrate the effectiveness of the proposed control strategy.